Restrict tag-update for version generation to cached git repos.

build/generate_version.py

 #!/usr/bin/env python
 # Copyright 2014 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Script to set v8's version file to the version given by the latest tag.
 
 The script is intended to be run as a gclient hook. The script will write a
 generated version file into the checkout.
@@ skipping 10 matching lines @@
 import subprocess
 import sys
 
 
 CWD = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
 VERSION_CC = os.path.join(CWD, "src", "version.cc")
 VERSION_GEN_CC = os.path.join(CWD, "src", "version_gen.cc")
 
 
 def generate_version_file():
-  # Make sure the tags are fetched.
-  subprocess.check_output(
-      "git fetch origin +refs/tags/*:refs/tags/*",
+  # Make sure the tags are fetched from cached git repos.
+  url = subprocess.check_output(
+      "git config --get remote.origin.url",
       shell=True,
-      cwd=CWD)
+      cwd=CWD).strip()
+  if not url.startswith("http"):
+    subprocess.check_output(
+        "git fetch origin +refs/tags/*:refs/tags/*",
+        shell=True,
+        cwd=CWD)
   tag = subprocess.check_output(
       "git describe --tags",
       shell=True,
       cwd=CWD,
   ).strip()
   assert tag
 
   # Check for commits not exactly matching a tag. Those are candidate builds
   # for the next version. The output has the form
   # <tag name>-<n commits>-<hash>.
@@ skipping 68 matching lines @@
     with open(VERSION_GEN_CC, "w") as f:
       f.write(version_file_content)
     # Log what was calculated.
     print log_message
 
   return 0
 
 
 if __name__ == "__main__":
   sys.exit(main())